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2014 October 15

Click for full size image (left) or movie (right).

Supra-Arcade Downflowing Loops

On October 10th, XRT observed an interesting series of downflows outside of Active Region 12182 that were associated with a C1.0 flare in the region. XRT was taking rather long exposures at the time, which saturated the active region but allowed for the detection of the faint sunward flows seen in the movie above. These structures are likely to be signatures of retracting (shrinking) magnetic field loops that formed as the overlying field was reconfigured by the flare-producing magnetic reconnection event. Such loops are referred to as "Supra-Arcade Downflowing Loops" (SADLs). SADLs are closely related to "Supra-Arcade Downflows" (SADs), which are plasma voids thought to be wakes behind the SADLs. (See this previous XPOW for a nice example of SADs.) In the observations shown here, the loops are clear enough but the voids are less apparent, perhaps because the density of the surrounding plasma was insufficient to produce robust voids and/or because the mostly face-on viewing angle of the loops was less favorable for seeing the voids. A cartoon of this model, from Savage et al. (2013), can be found here.

Keywords: Downflows, Flare
Filters: Be_thin

(Prepared by Masumi Shimojo and Patrick McCauley)

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